Rivet hammer die set retainer



Ma 1964 H. L. HEDDEN ETAL RIVET HAMMER DIE SET RETAINER Filed Jan. 12, 1961 Jm/eml'm f/AZZY L. HEDDE-M AA/D EuuoLPH D. 851. VEN fla zmHmfizam/m 7 atlma'ya.

United States Patent 3,124,981 RIVET z R DIE SET RETAINER Harry L. Hedden, Midiothian, and Rudolph D. Selven, Chicago, 151., assignors to Union Tank Car Company, Chicago, Iii, a corporation of New .Iersey Filed Jan. 12, 1961, Ser. No. 82,295 9 Claims. (Cl. 78-46) The present invention relates to rivet hammers and, in particular, to impact type rivet hammers adapted to be pneumatically operated to effect a reciprocal riveting operation.

It is an object of the present invention to provide a rivet hammer which will not discharge its component parts into the air when improperly operated.

It is another object of the present invention to provide a rivet hammer in which its component parts cannot be ejected during improper operation, yet can be easily disassembled if damaged as a result of improper operation.

It is a further object of the present invention to provide on a rivet hammer a rivet die set which is prevented from being expelled from the rivet hammer during its improper operation, thereby preventing injury and damage to an operator or surrounding apparatus.

The above and other objects are realized in accordance with the present invention by providing a rivet hammer which is adapted to deform an end of a rivet. The rivet hammer comprises a barrel within which is positioned a reciprocable piston adapted to drive a rivet die set. The rivet die set is reciprocably supported in the barrel to deform the end of a rivet during a riveting operation in a manner well known. In order to prevent ejection of the rivet die set during improper operation of the rivet hammer, a retaining mechanism coacts with the rivet die set. The retaining mechanism is inoperative during a conventional riveting operation and is operative to prevent ejection of the rivet die set from the rivet hammer when it is inadvertently operated, i.e. when it is not engaging a rivet or the like. In contrast with commercially available rivet hammers which are rendered inoperative when the component parts are jammed or damaged after inadvertent operation, a rivet hammer embodying the features of the present invention is not rendered inoperative since any jammed or damaged components can be readily removed and thereafter replaced.

The present invention, both as to its organization and method of operation, taken with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawing, in which:

- FIG. 1 is a front elevational view of a rivet hammer embodying the features of the present invention shown in position following a riveting operation;

FIG. 2 is an enlarged fragmentary view taken along line 2-2 of FIG. 1, illustrating the hammer of FIG. 1 in a first operational position;

FIG. 3 is a sectional view similar to FIG. 2, illustrating the hammer of FIG. 1 in another operational position;

FIG. 4 is a sectional view similar to FIGS. 2 and 3, illustrating the hammer in yet another position; and

FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 2.

Referring now to the drawing and in particular to FIG. 1, there is illustrated a pneumatic impact type rivet hammer shown in a position following a riveting operation. The rivet hammer 10 is used to rivet together a pair of plates 50 and 52 and, in particular, operates to deform an end of a rivet 54 which is held in riveting position by a suitable support 56.

Briefly, the rivet hammer 10 is pneumatically operated and, in this connection, includes a pneumatic line 2 interconnecting a suitable supply of compressed air or 3,1243% Patented Mar. 17, 1964 the like (not shown) and a barrel 1 of the hammer 10. The compressed air supplied by the pneumatic line 2 is periodically supplied by an actuator arrangement (not shown) to a moving piston 8, located within the barrel 1. The actuator arrangement (not shown) is preferably located within the barrel 1 but can, alternatively, be located at a point spaced from the hammer 10. In any event, the moving piston 8 reciprocates in the barrel to drive a rivet die set 4 which engages the deformable end of the rivet 54. The rivet die set 4 cannot be ejected from the barrel when the hammer 10 is fired into the air because of a retaining mechanism 3. The retaining mechanism 3 is detachably secured to the barrel 1 of the hammer 10 and coacts with the rivet die set 4 only when the hammer 16 is improperly operated.

Considering now the components of the rivet hammer Iii in greater detail and referring to FIG. 2, the piston 8 is shown fragmentarily, and comprises a cylindrical configuration somewhat undersized relative to the inner dimension of the barrel 1. As shown, its right end 8a of the piston is perpendicularly related to its axis to form an impact surface for engaging and driving the rivet die set 4. The rivet die set 4 is freely mounted on the barrel 1 by the retaining mechanism 3 such that its left half is dispoesd within the barrel 1 while its right half extends forwardly of the barrel 1 for engaging the rivet 54. The rivet die set 4, as indicated above, is reciprocably driven by the piston 8 and, when the hammer It) is in proper position, the rivet die set 4 repeatedly engages the deformable end of the rivet 54. Hence, the impact force of the piston 8 is transmitted directly to the rivet 54 by the rivet die set 4.

More particularly, the rivet die set 4 comprises a shank 58 positioned within the right end of the barrel :1 and, further, a die head 14 extending outwardly and to the right of the barrel 1. The die head 14 is provided in its right end with a die cavity 653 which accommodates the deformable end of the rivet 54. The die cavity 60, as illustrated, is spherical in construction and, accordingly, forms a round headed rivet 54. 0d course, the die cavity can have any particular configuration to impart to the deform-able end of the rivet 54 any desired head. In any event, nothwithstanding the rivet configuration desired, the rivet die set 4 is selected so that its die cavity 60 has a configuration to correspond with the diarnter and length of the shank of the rivet 54. The die head 14 of the rivet die set '4 includes a transversely extending aperture 12 which coacts with the retaining mechanism 3 and, in particular, accommodates a portion of the retaining mechanism 3.

In order to prevent ejection of the rivet die set 4 from the barrel ll when the hammer It} is inadvertent-1y triggered, the retaining mechanism 3 is detachably secured to the barrel 1. The retaining mechanism 3 specifically comprises a sleeve 16 which partially extends about the right end of the bar-rel I and partially extends rightwardly of [the barrel to surround the die head 14. As shown, the right end of the sleeve 16 terminates short of the die head 14 so as not to interfere with the deforming of the rivet 54. In addition, as shown only in FIG. 1, opposite sides of the sleeve 16 adjacent its right end are cut away as indicated at 19 to thereby define a pair of arms 23. The cut-away portions 19 permit riveting of rivets located adjacent ang-led constructions or shoulder constructions, with the result that the use of the hammer it? is in no way restricted by the retaining mechanism 3. The sleeve 16 and the rivet die set 4 are interconnected by a retaining pin 20. The retaining pin 29 is received in an oversized aperture 12 of the rivet die set 4 and is disposed in oversized slots is defined in arms 23 of the sleeve 16, whereby the retaining pin 2% is movable longitudinally of the sleeve 16. Disassembly of the retaining pin 28 and the sleeve 16 is prevented by the coaction of the pin 26 with Was-hers 21 and 22'. The Washers 21 and 22 slidably engage the portions of the arms 23 adjacent the slots 18 and coact, respectively, with the enlarged head of the pin 28 and a cotter pin 24 inserted in a suitable opening provided at the lower end of the pin 28. By this arrangement, the retaining pin 20 is slidably secured to the sleeve 16 and since the pin 20 is disposed within the aperture 12, it can be moved :by and with the rivet die set 4.

The retaining mechanism is detachably secured to the bar-rel 1 by the coaction of a coil spring 28 and registered grooves 32 and 34 in the barrel 1 and in the sleeve 16, respectively. As best shown in FIG. 2 the grooves 32 and 34 are semi-circular in cross-section to readily accommodate the circular sectional spring 28. As best seen in FIGS. 2 and 5, a loading aperture 38 is defined in the sleeve 16 in such a manner as to provide access to the registered grooves 32 and 34 from outside of the sleeve 16. Specifically, during mounting of the retaining mechanism 3 to the barrel 1, one end of the spring 28 is inserted through the loading aperture 38 and into the registered grooves 32 and 34, and thereafter the remainder of the spring 28 is pushed into the circular passageway formed by the registered grooves 32 and 34.

With the spring 28 completely stored in the registered grooves 32 and 34, the sleeve 16 is detachably secured to the barrel 1 and relative longitudinal movement is prevented. In addition, since the sleeve 16 is connected to the rivet die set 4 by the retaining pin 20, the rivet die set 4 is also detachably secured to the barrel 1. However, because of the play existing between the retaining pin 24 and the slots 18 and between the retaining pin 20 and the aperture 12, the rivet die set 4 is slidably secured to the barrel 1 to permit its reciprocal riveting motion.

Assuming that it is desired to rivet plates 50 and 52, the shank of the rivet 54 is inserted through aligned open ings in the plates 50 and 52 until its pro-formed head engages plate 52. The rivet support 56 is moved into engagement with the pre-formed head to condition the rivet 54 for riveting. Then the rivet hammer is moved toward the rivet 54 into operative position so that the rivet die set 4 engages the undeformed shank. The actuating arrangement (not shown) is operated to cause compressed air to be delivered from the line 2 to the moving piston 8, with the result that the piston 8 moves rapidly to the right, as seen in FIG. 2, into driving engagement with the rivet die set 4. Immediately, the rivet die set 4 moves from the position shown in FIG. 2 toward the right, i.e., outwardly of the right end of the barrel 1. Specifically, the left portion of the aperture 12 engages the retaining pin 28 and moves the retaining pin and washers 21 and 22 to the right. However, because the rivet 54 is backed-up by the rivet support 56, the retaining pin 20 does not engage the right portion of the slots 18. When the actuating arrangement (not shown) cuts off the supply of air to the piston 8, the die set 4 rebounds and moves to the left. Movement of the die set 4 to the left into the barrel 1 is limited by the annular shoulder 15 defined between the shank 58 and the larger diameter die head 14. However, since the actuator arrangement (not shown) functions only to pneumatically drive the piston 8 and rivet die set 4 to the right, the annular shoulder 15 is not positively driven against the end of the barrel 1.

Assuming that the rivet hammer 18 is improperly operated, i.e., the hammer is operated when the rivet die set 4 is not in engagement with a rivet 54 or other support structure, compressed air is supplied to piston 8, with the result that piston 8 moves to the right, as shown in FIG. 2, into engagement with the rivet die set 4. The rivet die set 4 moves from the position shown in FIGS. 2 and 3 into the position shown illustrated in RC. 4. More specifically, as the rivet die set 4 moves to the right, the left portion of the aperture 12 engages the retaining pin 20 and moves the retaining. pin 20 and its associated Washers 21 and 22 to the right. Since the rivet die set 4 is not supported by a rivet 54 or other structures, it continues rightwardly, beyond the position in which it would normally stop during the riveting operation, until the retaining pin 20 abuts against the right portion of the slots 18 in the sleeve 16. Hence, the retaining pin 20 moves from the left end of the slots 18 to the right end of the slots 18, as shown respectively in FIGS. 2 and 4. When the rivet die set reaches the position illustrated in FIG. 4, its movement is arrested. Specifically, movement of the rivet die set 4 is prevented by the coaction of the left portion of the aperture 12 and the retaining pin 20, the retaining pin 20 and the right portion of the slots 18 of the sleeve 16, the groove 34 in the sleeve 16 and the coil spring 28, and the coil spring 28 and the groove 32 in the barrel 1. In short, the kinetic energy of the moving rivet die set 4 is absorbed by the retaining pin 20, the sleeve 16, the spring 28, and the barrel 1.

Thus, it will be appreciated that when the hammer 10 is inadvertently operated, rivet die set 4 can neither be disassembled from the hammer 10 nor projected or propelled into the air with the resultant possibility of injury to the operator or surrounding apparatus.

From the foregoing description it should be understood that, although the rivet hammer 10 is repeatedly operated in an improper manner, it is not rendered completely inoperative. As would be expected after repeated inadvertent operation of the hammer 10, the retaining pin 20 becomes deformed as a result of the rivet die set 4 repeatedly driving the retaining pin 20 against the right portions of the slots 18. However, unlike presently available hammers in which the retaining pins or means must be removed with auxiliary devices, the retaining pin 20 is easily removed and replaced because'of the oversized relation. of the aperture 12 in the die set 4 and, also, of the slots 18 in the sleeve 16. In addition, the existence of play between the retaining pin 20, the die set 4, and sleeve 16 permits a short length retaining sleeve to be used, since if a rivet die set having an aperture of the same size as the retainer pin is used, the slots in the sleeve would have to be extended and, accordingly, the sleeve would have to be lengthened. Thus, the sleeve 16 is lighter in Weight and is more remotely spaced from the end of the rivet die set than a retaining sleeve having an aperture of the same size as the retainer pin.

It should also be understood that by providing cutaway portions 19 in the sleeve 16 the use of the hammer 10 is in no way restricted by the retaining mechanism 3. Specifically, rivets located adjacent angled or shouldered constructions can be readily deformed without interference of the sleeve 16. In addition, the cut-away portions 19 permit viewing of the rivet such that an operator can readily watch its actual deformation and, also, readily determine whether or not it is adequately deformed. Finally, the cutaway portions 19 permit viewing of the retaining pin 20 so that the operator can readily determine the extent, if any, of deformation of the pin 20 and, further, can determine when the pin 20 should be replaced.

It should be further appreciated that the present invention is characterized by being readily adaptable to rivet hammers presently in use. For example, many of the commercially available rivet hammers can be readily adapted to embrace the present invention by merely drilling a hole in a rivet die set, forming a semi-circular groove in a barrel, and, thereafter, assembling the retaining mechanism 3 to the modified hammer. Hence, with a minimum of expense and labor, presently available rivet hammers may be readily and easily modified.

While the embodiment described herein is at present considered to be preferred, it is understood that various modifications and improvements may be made therein, and it is intended to cover in the appended claims all such modifications and improvements as fall within the true spirit and scope of the invention.

What is desired to be claimed and secured by Letters Patent of the United States is:

1. A pneumatic hammer comprising a hammer barrel, a hammer means positioned within said barrel for reciprocating movement, said hammer means normally moving less than a predetermined distance when said hammer is properly operated, a first retaining means formed within said hammer means, a retaining mechanism detachably secured to said barrel and comprising a sleeve positioned around said hammer barrel and said hammer means, said sleeve having second retaining means formed therein, and a third retaining means movably supported from said sleeve for movement axially of said sleeve and said hammer means for coacting with said first retaining means and said second retaining means for preventing ejection of said hammer means from said barrel during inadvertant operation of said hammer.

2. A pneumatic hammer comprising a substantially cylindrical hammer barrel having a longitudinal aperture formed therein, a substantially cylindrical hammer element positioned Within said aperture for reciprocating movement Within said aperture, a rivet die set partly positioned within said barrel and movable responsive to the movement of said hammer element for reciprocating movement within said aperture, said rivet die set normally moving less than a predetermined distance when said hammer is properly operated, a first retaining slot formed within said rivet die set, a retaining mechanism comprising a substantially cylindrical sleeve portion positioned around said hammer barrel and said rivet die set, said sleeve being detachably secured to said hammer barrel, a pair of diametrically opposed retaining slots formed within said sleeve, a retaining element positioned within said first retaining slot and said pair of diametrically opposed retaining slots and slidably attached to said sleeve, the Width of said retaining element being substantially smaller than the length of said first retaining slot, the length of said pair of diametrically opposed retaining slots being such so as to enable said rivet die set to move a distance exceeding said predetermined distance.

3. A pneumatic hammer comprising a movable hammer means, a barrel enclosure for said movable hammer means, said movable hammer element normally moving less than a predetermined distance when said hammer is properly operated, said hammer element having a first retaining means formed therein, said barrel enclosure having a second retaining means formed therein, a retaining element positioned within said first retaining and said second retaining means and slidably secured to said barrel enclosure, said first retaining means, second retaining means, and retaining element being interrelated dimensionally so that said hammer element is able to exceed said predetermined distance.

4. A pneumatic hammer comprising a movable hammer element, said movable hammer element normally moving less than a predetermined distance when said hammer is properly operated, a barrel enclosure for said movable hammer element, said hammer element having a first retaining aperture formed therein, said barrel enclosure having a second retaining aperture formed therein and a third retaining aperture formed therein, a retaining element positioned within said first, said second, and said third retaining aperture and slidably secured to said barrel, the width of said first retaining aperture being substantially greater than the width of said retaining element, the diiference between the width of said first retaining aperture and the width of said retaining element plus the difierence between the width of said retaining element and the length of said second retaining aperture or said third retaining aperture being substantially equal to said predetermined distance.

5. A pneumatic hammer comprising hammer barrel means, a movable hammer element, said movable hammer element positioned within said barrel means for reciprocating movement within said barrel means, said movable hammer element normally moving less than a predetermined distance when said hammer is properly operated, said hammer element having a first retaining aperture formed therein, said barrel means having a second retaining aperture formed therein and a diametrically opposed third retaining aperture formed therein, a retaining element positioned within said first retaining aperture, said second retaining aperture and said third retaining aperture and slidably secured to said barrel, the width of said first retaining aperture being substantially greater than the Width of said retaining element, the difference between the width of said first retaining aperture and the width of said retaining element plus the difference between the width of said retaining element and the length of said second retaining aperture or said third retaining aperture being substantially equal to said predetermined distance.

6. In a pneumatic hammer of the type including a hammer element positioned within a hammer barrel; means supported from said barrel, a rivet die set positioned within said barrel and movable responsive to the movement of said hammer element for reciprocating movement within said hammer barrel, said rivet die set normally movable less than a predetermined distance when said hammer is properly operated, a first retaining aperture formed Within said rivet die set, a pair of diametrically opposed retaining slots formed within said supported means, a retaining element positioned within said first retaining aperture and said pair of diametrically opposed retaining slots, the diameter of said first retaining aperture being substantially greater than the diameter of said retaining element, the difference between the diameter of said first retaining aperture and the diameter of said retaining element plus the difference between the diameter of said retaining element and the lengths of the diametrically opposed retaining slots being substantially equal to said predetermined distance.

7. In a pneumatic hammer of the type including a hammer means located within a barrel, a detachable retaining mechanism supported from said barrel, a rivet die set partially located within said barrel and including first retaining means extending therethrough, and second retaining means slidably supported from said retaining mechanism and extending through said first retaining means in said rivet die set, and the retaining mechanism, said second retaining means being movable axially of and relative to said rivet die set, and said second retaining means permitting reciprocation of said rivet die set during a normal riveting operation, yet restricting ejection of said rivet die set from said barrel during improper operation of the hammer.

8. A pneumatic hammer comprising a hammer barrel, a hammer means positioned within said barrel for reciprocating movement, retaining means formed in said hammer means, a retaining mechanism detachably secured to said barrel, said mechanism including a sleeve arrangement positioned around and forward of said hammer barrel and a retaining pin slidably supported from said sleeve for movement axially of said sleeve and said hammer means for coacting with said retaining means to provide a lost motion connection interconnecting the hammer means and the sleeve arrangement, the retaining mechanism and associated means permitting reciprocation of said hammer means during a riveting operation of the hammer and restricting ejection of the hammer means from said hammer during improper operation of the hammer.

9. The pneumatic hammer of claim 1 wherein said sleeve of said retaining mechanism embodies a cut-away structure that permits disposition of the hammer means ad- References Cited in the file of this patent UNITED STATES PATENTS Winans May 18, 1897 Richards Mar. 11, 1902 8 Keeley Nov. 24, 1908 Johnson Dec. 17, 1912 Chaplin June 22, 1915 Osborne Jan. 4, 1916 Tissler July 3, 1928 FOREIGN PATENTS Great Britain 1908 

1. A PNEUMATIC HAMMER COMPRISING A HAMMER BARREL, A HAMMER MEANS POSITIONED WITHIN SAID BARREL FOR RECIPROCATING MOVEMENT, SAID HAMMER MEANS NORMALLY MOVING LESS THAN A PREDETERMINED DISTANCE WHEN SAID HAMMER IS PROPERLY OPERATED, A FIRST RETAINING MEANS FORMED WITHIN SAID HAMMER MEANS, A RETAINING MECHANISM DETACHABLY SECURED TO SAID BARREL AND COMPRISING A SLEEVE POSITIONED AROUND SAID HAMMER BARREL AND SAID HAMMER MEANS, SAID SLEEVE HAVING SECOND RETAINING MEANS FORMED THEREIN, AND A THIRD RETAINING MEANS MOVABLY SUPPORTED FROM SAID SLEEVE FOR MOVEMENT AXIALLY OF SAID SLEEVE AND SAID HAMMER MEANS FOR COACTING WITH SAID FIRST RETAINING MEANS AND SAID SECOND RETAINING MEANS FOR PREVENTING EJECTION OF SAID HAMMER MEANS FROM SAID BARREL DURING INADVERTENT OPERATION OF SAID HAMMER. 